10:34PM
The transitional pattern will continue for the next 7 days, through Christmas Day. Computer model solutions will likely be somewhat unstable during this time. My best guess at the pattern is that we will see drier and cooler air move in through early Thursday. Another low pressure area will traverse the region Thursday night and Friday. Some of the chilly air may be hard to scour out and make precipitation type issues for the forecast. Right now the thinking is that we may see some areas, especially north and west of Boston, start out as some snow late Thursday night into Friday before the warm sector blasts into the region and everyone ends up mild and wet. But as the low pressure area passes, colder air will wrap back in from the north and west. A race between the cold and the end of the precipitation makes it uncertain as to whether or not a period of snow will occur Friday night. Either way, we may see additional periods of snow on Saturday as an upper low pressure area comes across the region in a newly arrived cold air mass, with a surface low sitting just offshore. This should clear out on Sunday, and early next week (Christmas Eve & Christmas Day) should also be cold and mainly dry, though we will need to watch the orientation of the wind field as an ocean wind may set up and bring in ocean effect snow showers. There are many days to fine tune this.
Updated forecast for eastern MA, RI, and southern NH…
TONIGHT: Mostly cloudy. Scattered rain showers except rain or snow showers in areas well north and west of Boston. Lows 33-38. Wind W increasing to 10-15 MPH.
WEDNESDAY: Partly to mostly sunny. Isolated rain or snow showers. Highs 40-45. Wind NW 10-20 MPH with gusts around 25 MPH.
WEDNESDAY NIGHT: Mostly clear. Lows from the upper 10s inland valleys to middle 20s coast. Wind NW to N decreasing to around 10 MPH.
THURSDAY: Sunny. Highs around 40. Wind light variable.
FRIDAY: Cloudy with mix to rain morning. Mostly cloudy with rain showers afternoon. Variably cloudy with rain showers changing to snow showers at night. Low 32. High 50.
SATURDAY: Cloudy. Periods of snow. Low 24. High 33.
SUNDAY: Partly sunny. Chance of light snow showers. Low 22. High 35.
MONDAY – CHRISTMAS EVE: Partly cloudy. Low 18. High 37.
TUESDAY – CHRISTMAS DAY: Partly sunny. Low 17. High 33.